R ggplot添加新的roc曲线

Question

我想在ggplot图表中添加ROC曲线,但它会返回错误代码.

  library(ggplot2)
  library(plotROC)

  set.seed(2529)
  D.ex <- rbinom(200, size = 1, prob = .5)
  M1 <- rnorm(200, mean = D.ex, sd = .65)
  M2 <- rnorm(200, mean = D.ex, sd = 1.5)

  test <- data.frame(D = D.ex, D.str = c("Healthy", "Ill")[D.ex + 1], 
                     M1 = M1, M2 = M2, stringsAsFactors = FALSE)
  plot<-ggplot(longtest, aes(d = D, m = M1 )) + geom_roc() + style_roc()
  plot

没关系,但如果我添加新的ROC线它的返回错误

plot<-ggplot(longtest, aes(d = D, m = M1 )) + geom_roc() + style_roc()
plot+ggplot(test, aes(d = D, m = M2)) + geom_roc()

p + o中的错误:二元运算符的非数字参数另外:警告消息:"+"的不兼容方法("+ .gg","Ops.data.frame")

我如何添加新的线条和颜色所有线条不同的颜色,并添加图例

Answer 1

将数据框从宽格式转换为长格式,然后将变量名称映射到美学映射中的线条颜色:

ggplot(melt_roc(test, "D", c("M1", "M2")), 
       aes(d = D, m = M, color = name)) + 
    geom_roc() + 
    style_roc()

你也可以这样做,如果你想:

ggplot() + 
  geom_roc(aes(d = D, m = M1, color="roc1"), test) + 
  geom_roc(aes(d = D, m = M2, color="roc2"), test) + 
  scale_color_manual(values=c("roc1"="red", "roc2"="blue"), 
                     name="color legend", guide="legend") + 
  style_roc()